For recording increased volume of information in recent years and continuing, mass information recording media, such as CD-ROM (Compact Disk Read Only Memory) and CD-R (Compact Disk Recordable) are widely used. Further, phase-change type optical recording media, such as CD-RW (Compact Disk Rewritable) having affinity to the CD-ROM and CD-R, have been developed and popularly used. The Orange Book part III (ver 1.0) published in October, 1996 standardizes twice linear speed recording (24 to 28 m/s) with such phase-change type optical recording media.
Optical disk apparatuses that are capable of information recording, reproduction, and rewriting at high density are also available for the phase-change type optical recording media.
For example, the JPA 2001-283443 discloses required recording conditions such as a power level and a pulse width of recording pulses of a laser light when a user records information on the optical disks such as CD-R/RW, DVD−R/RW, and DVD+R/RW.
Further, the JPA 2002-334433 discloses technology for an optical disk apparatus to determine recording strategy with reference to recording strategy information beforehand stored in an optical disk.
Generally, when a user records data on a recordable optical disk such as CD-R/RW, DVD−R/RW, and DVD+R/RW, recording conditions such as power levels and pulse widths of recording pulses (for example, parameters as indicated by the JPA, 2001-283443) of the laser light source for recording have to be determined. The recording conditions are called the recording strategy. Since the optimal recording strategy varies with properties of the recording material and the substrate of an optical disk, kind of the disk, and disk maker, the optimal parameters have to be determined for every optical disk.
According to the technology disclosed by the JPA, 2002-334433, an optical disk apparatus determines the optimal recording strategy with reference to the optimal recording strategy information that is beforehand recorded on the optical disk. However, the recording conditions written on the optical disk may not be applicable to all makers' optical disk apparatuses. This is because system parameters, such as laser wavelength, numerical aperture (NA) of an objective lens, rising time of a recording pulse, and the like differ from maker to maker of the optical disk apparatuses. Therefore, even if the technology of the JPA, 2002-334433 is used, and the optimal recording strategy information stored in the optical disk is used, optimal information recording may not be obtained.
Further, the optical disk apparatus may be capable of reading information, such as an identification of the maker and a version/model identifier of the optical disk from the loaded optical disk, and searching for recording strategy information possibly stored in the optical disk apparatus.
However, if the optical disk is an unknown optical disk, the strategy information of which is not registered by the optical disk apparatus, the optimal recording strategy cannot be set up. In this case, recording usually has to be carried out with a predetermined default recording strategy.
When recording information on optical disks, such as CD-R/RW, DVD−R/RW, and DVD+R/RW, it is necessary that recording be carried out at a laser power level (recording power level) that provides the optimal recording quality. For this purpose, a trial writing area, called PCA (Power Calibration Area), is usually prepared in optical disks, such as CD-R/RW, DVD−R/RW, and DVD+R/RW, and an optical disk apparatus adjusts the recording power through an OPC (Optimum Power Control) process, wherein trial writing is performed on the trial writing area, and the optimal recording power is determined from results obtained.
Thus, when information recording is carried out on an unknown optical disk without the optimal strategy information, the optical disk apparatus records at one of a predetermined basic strategy and a recording power level determined through the OPC process. Under this situation, there are cases where neither the predetermined basic strategy nor the recording power level determined through the OPC process is appropriate.